Obsession
by Natsu-z
Summary: The twins discover something better than fighting and become obsessed with it. Ruffnut / Tuffnut. Incest.
1. Chapter 1

**Obsession**

**_Chap 1_**

The hot water involved the young Viking girl and she sighed deeply, sinking until the water covered everything but her face. She was tired and worn out, her arms hurt.

Ruffnut held her breath and immersed, staying as long as she could under the under and then coming back to the surface a few moments later. She opened her eyes slowly to find her twin sitting just in front of her.

"What are you doing here?" Both shouted at each other, she covered her breasts with her arms.

"Get out, Tuffnut! I was here first!" She pushed him with one arm, the other still covering her chest.

"I didn't see you! Why were you under the water?" He shoved her back.

She advanced to hit him, hands clenched in fists; the boy tried to stop her and accidentally placed a hand on her breast.

Both froze for a second, faces in bright crimson. They stared at the pearly white form covered by the calloused hand.

"You jerk!" Ruffnut pushed his hand away, pissed off that it was still there, and slapped his face with all her strength, leaving a red mark. "Now GET OUT!"

They exchanged angry glares as he brushed his golden hair out of his face and then stood up, making his sister blush again and look away, then got out of the tub.

_Damn it! He could have covered himself!_She squeezed her eyes shut, trying to block the image of Tuffnut standing naked right in front of her.

Later both went to the training arena, flying on their Zippleback, to meet the others. Not talking to each other.

"If you scratch right here…" Hiccup said demonstrating to the others where the weak point of the dragons was: the throat.

Ruff and Tuff choose the same head to scratch.

"Get the other!" He said shoving her hand away.

"No way! I choose this one first!" She spit back.

"You did not!" He hit her forehead with his and she pushed him away.

In no time they were rolling on the floor and each head of the Zippleback grabbed one of them, parting the fight.

The dragon flew home, carrying the twins and threw them on their bedroom floor. The got up and adjusted their clothes, still not talking to each other.

Tuffnut grunted annoyed and walked out, slamming the door behind him.

His twin removed her helmet and laid on her bed, hugging herself, the Zippleback purred and flew to the side of the bed, each head resting on one side of the girl.

Ruffnut smiled weakly and caressed each head, her thoughts focused on her twin brother. Shivers ran down her spine as she thought of those arms around her and she sighed, hating herself for thinking such things.

* * *

"I hate Terrible Terrors!" Tuffnut stormed into the bedroom, hours later, waking his sister and the two-headed dragon. He sat down at the bench under the window, rubbing his face, covered by ashes and burns.

"What happened?" The girl stood up and walked towards him, taking his hands off his face to look at the bruises.

"Damn little bastard…" He cursed.

She shook her head, knowing what had happened. "Wait here, I'll take care of this."

He crossed his arms and waited for her to return with a small bowl with water and bandages. Ruffnut sat beside him and he turned to her, placing one leg at each side of the bench, allowing her to take care of his bruises. He watched her face as she cleaned his, he had never noticed how pretty she was. Her golden curls cascaded down her chest and stooped by her thin waist, his eyes lowered studying her thighs. He pictured his hands on them, slowly running up under her skirt.

"I'm sorry." Her voice brought his eyes back up to meet hers.

"Huh?" He frowned.

"Well, for… that." She cleaned his cheek.

"Oh… I'm sorry, too. I shouldn't have touched your…" He lowered his eyes for a moment and then back at her.

Both blushed a little at the memory of the events as Ruffnut finished his face and left him.

The boy watched as she walked away and closed the door behind her, he couldn't stop thinking about how it felt to touch her. Her skin was so soft, it was wet and warm, so pale and her flesh so firm, he wondered what would feel like if he had touched her in other places…

The door cracked open and he saw his twin walk in once again. The Zippleback that was still laying on Ruffnut's bed opened one eye of each head to see who was entering and then went back to sleep as she sat on the floor, close to the bed and started to brush her hair.

"Hey, dragon butt…" He said mockingly, standing up.

"Call me that again and you're dead, lughead…" She spit back, closing her eyes and reclining to lean against the bed.

She ran the brush lazily along her golden hair, when she felt the brush be gently taken out of her hand. She turned around to see what had happened and found Tuffnut sitting on the bed, behind her and holding the brush.

"Hold still, dummy." He said, turning her face away.

The girl felt a shiver run down her spine when his harsh fingers brushed against the back of her neck as he held a lock of hair. She bit her lip and unconsciously leaned her head back as she whished feverously for those fingers to slide down her body and touch her.

Her brother caught his breath as he felt her head heaving on his crossed legs and almost touching his crotch.

"You're _not_ helping." He muttered angrily.

She raised her head and looked back at him; he had his arms crossed and a grumpy expression on his face.

"Finish it." She commanded, turning her back to him.

Ruffnut pushed her forwards, opening space for him to slide to the floor and sit behind his sister, who elbowed him in return, taking the brush from his hand.

She gathered all her hair over one shoulder, exposing the side of her neck and the opposite shoulder; and ran the brush down on the locks lazily.

She froze when she felt his hands on the sides of her waist and his lips on her neck, her heart seemed to have found a way up to her throat, the brush fell from her hand and she couldn't breathe. His arms sneaked around her slim waist as he sucked her neck, making the girl squirm in his arms and moan.

Ruffnut recovered her reason and shoved him away, scooting to the opposite direction.

"Have you lost your bloody mind?" She panted.

"Haven't you?" He reached out grabbing her wrists and dragging her back, to where she had been. She kept tugging her arms, trying to break free from his grip, but she was not able to do so and was pressed against his muscular chest. She punched his chest in protest, but it was useless, Tuffnut held her still forcibly and pressed his lips against hers. Ruffnut wanted to part, but was dying to response, her arms felt like jelly and her heart was fluttering.

Encouraged by her complete stillness he parted her lips and invaded her mouth with his tongue, his hands left her wrists and moved to her back, he felt her body relaxing and her tongue moving with his. She raised her hands weakly to grab his tunic and angled her head to reach further inside his mouth, receiving a low moan as reward.

He parted out of breath and removed her waistcoat, bringing his lips to her exposed skin, kissing and sucking, hearing her moans, as his hands worked on the ties of her clothes. Ruffnut's hand found the opening of his tunic and explored the blonde's nicely proportioned chest, feeling every muscle response to her touch.

The boy grunted, taking her hands from his chest and holding them up, above her head. Tuffnut bent down and captured her lips once more, parting her thighs with his own and settling his hips between them. The boy jerked his hips forward a bit more and she moaned against his mouth; feeling his erection be pressed against her. He released her hands, and undid her shirt completely, his harsh hands squeezed her breasts making the girl arch beneath him and rub against his dick, her fingers tangling themselves in his long hair pulling at it lightly.

He parted and stared down at the panting Viking girl, her face was flushed and her hair was messy around her head, she closed her eyes pushing him down and bringing his face to her breasts. He sucked her pinky nipples, hearing her voice crack with pleasure; his hands explored downwards sliding her remaining clothes off and lowering the border of his pants.

A gasp escaped her lips as he pressed his hard shaft against her exposed entrance and leveled his face to hers, her arms wrapped around him shakily.

She winced as he entered her, his hands holding her hips from withdrawing, he pushed further and she felt him shudder. His grip seemed to have weakened as he moved slowly.

"I-It hurts…" She cried out, squirming beneath him and burying her face on his shoulder.

He ignored her, the overwhelming sensations coursing though his body made him push harder and growl, his fingers digging on her tender flesh as she whimpered.

Slowly the pain faded and she clung to him, biting her bottom lip as his their hips moved faster and the breaths they drew became shorter.

"Tuff…" She whined against his ear, arching her back.

Her silky walls squeezed him tightly, the friction of his thrusts making the pleasure almost unbearable, with a throaty snarl he gripped her hips tightly and plunged himself forcefully inside her until he filled her with liquid heat.

The boy pressed his forehead against hers, both panted heavily. A mess of blond hair covered their sweaty faces.

"You're shivering." She whispered as she opened her eyes and brushed his hair away from his face.

"I'm fine." He smiled faintly and pulled himself out, collapsing on top of her.

* * *

**Please, let me know what you think...**

**Reviews will encourage me to write chap 2 :D**


	2. Chapter 2

Huge thanks to everyone who reviewed. You guys rock!

This chapter is a little shorter, I was not very inspired…

I promise the next one will be longer :)

* * *

**_Chap 2_**

The snow had already started to fall; the cold air blew strongly in the arena, making the training end sooner.

Astrid and Hiccup were the first to leave, leaving the other four teenagers behind.

"So, let's fly through the blizzard? A race?" Snotlout tapped the side of his Monstrous Nightmare.

"Sure!" Fishlegs answered excited.

Tuffnut looked to his twin to know her opinion but she threw one of her braids over her shoulder and smiled mischievously shaking her head and got on their dragon.

"So..?" Snotlout insisted.

"We're going home, stuff to do." The blonde answered, getting on the dragon as well.

Zippleback took flight leaving the two boys in the arena confused, the Thorston twins never refused to do anything that involved competition.

Once Zip's feet touched the floor they hopped off and he threw his helmet somewhere in the room pulled her close, removing her one as well, to claim her mouth. She jerked back.

"What?" He muttered annoyed.

"He's watching." She answered pointing to their dragon, who was observing them.

"He watched the whole thing last time…" The boy stated, tearing her coat open.

Ruffnut glared at the dragon and then returned her attentions to Tuffnut. She wraped her arms around his neck and brought her lips to his, letting the boy deepen the kiss and run his hands on her sides under her heavy coat.

A shiver ran down her spine and she couldn't tell if it was because of the freezing air or his cold hands reaching under her shirt. He squeezed her breast and she moaned against his lips, her hands grasping his fur coat and her legs trembled; she parted panting to meet his smirk.

Before she could make another sound his mouth was on hers again and his hands was now running down her stomach as the other held her firmly.

Suddenly the door was slammed open and Ruffnut's first reflex was to shove him away and punch him, he shoved her back and they were on the floor, slapping each other.

"Stop you two! And go feed your dragon!" Their mother said loudly as she entered the room and parted the twins, pushing them towards the Zippleback and then shutting the door behind her.

Both looked at each other with wide eyes.

"Almost caught…" She whispered breathless.

* * *

The blond boy stretched out in the tub, the hot water making his muscles relax. The door cracked open and then was shut and locked, Tuffnut turned around to find his twin holding the key and grinning widely. He watched as she kicked off her boots and removed her clothes, then walked towards him as her fingers undid the braids he had done earlier on her golden locks.

Once she got into the tub he reached out and pulled her closer, placing her on his lap as his mouth covered hers. Ruffnut shifted in his embrace and parted her thighs, straddling him as she allowed him to deepen the kiss, the water level slapping softly against the sides of the tub with every move they made.

She pressed herself against him eagerly, torturing him as she ran her tongue over his and her hands rested teasingly on the sides of his hips, already feeling his stiffening member against her folds. He parted panting, his hands gripping the back of her thighs firmly and his dick aching. The boy swirled her over, one arm around her waist, the opposite hand on her inner thigh holding it up against his hipbone.

"Ah!" She gasped, holding onto the border of the tub as he entered her from behind.

"Shh, mom and dad will hear us!" He dropped her thigh and covered her mouth, whispering against her ear.

The water splashed, overflowed and dropped out of the tub; the friction was mind blowing, and still he pushed deeper and faster into his sister. He groaned with each thrust, sucking and biting the soft skin of her neck, clutching to her as she cried out and arched against him. She shut her eyes tight, moaning loudly and knowing it would leave a mark, her head fell backwards as she got closer.

He grunted also getting close to climax, his fingers digging on her flesh, but he wouldn't give in first.

He buried his face in her hair as he came, just after her. The girl's hands slipped from the border of the tub.

He steadied her body, holding her firmly, until she recovered herself and turned around to enlace his neck and kiss him softly.

"Was it…too much for you?" He parted, wrapping his arms around her waist.

"Nah, I like it rough…" She smirked.


	3. Chapter 3

Finally, chapter 3! Probably the last one… I'm content with my three chapters since there's not an elaborated plot…

Maybe, if have a great idea I'll add more chapters. Maybe not. Thanks to everyone who has been reading, reviewing and faving! I've never had so many fav story alerts *-*

And remember, feedback is always appreciated!

* * *

**_Chap 3_**

The sun woke Ruffnut before the dragon did. She opened her eyes lazily and then turned her face away from the sunlight and closed her eyes again, hoping to get to sleep.

"Hey, wake up!" Her twin pulled the furry blanket off her. "We have to meet the others."

She punched his arm and reached for the blanket. "Let's pretend we're sick…" She mumbled as she managed to recover her blanket.

"That's a nice idea." The boy grinned. "Scoot over." Tuffnut added as he lifted the blanket and managed to lie beside her.

"What are you doing?" She hissed trying to push him out of the bed.

"Stop pushing me, dragon butt!" He hissed back, holding her wrists.

"We're gonna get caught! Get out!" She warned, trying to break free from his grip. But it was useless.

"If Freyr and Freya could do it, why can't we?" He asked releasing her wrists slowly.

"Because they are Gods." She answered.

"Who cares?" He whispered approaching his face to hers.

Ruffnut looked up at him and closed the distance between them, pressing her lips to his. He kissed her back while one hand sneaked to her waist and pulled her closer. She was losing herself in the warm, musky taste of his mouth against hers when she heard steps and pulled away quickly.

"I bet everyone else cares." She said panting. "We better go." She added, removing his hand from her waist.

"I thought we would pretend we're sick." Tuffnut grimaced, not willing to get up.

"I changed my mind." She declared shoving him out of the bed.

"Ouch! You didn't need to do that…" He sighed and got up, walking towards the sleeping dragon on the middle of the room.

"Come on, Zip! Wake up!" He tapped the dragon's side and then followed his sister, out of the room.

"Hey, Ruff." He held her wrist and brought her back to their bedroom.

"What is it?" She asked avoiding his gaze.

"Look at me." He pressed her against the wall. She obeyed, meeting his intense blue eyes. "Why are you so afraid to get caught?" He asked.

She sighed deeply before answering. "I'm afraid they separate us… I-I'm afraid to lose you." The Viking girl threw her arms around her brother.

"So I'm not gonna let this happen." He hugged her back.

He let go of her and smiled, she smiled back and sat on her bed, grabbing her hair brush.

"Nobody said it is forbidden, right?" Her brother sat beside her and took the brush from her hand, taking a lock of hair and brushing it.

"What? That's just stupid! Of course it is wrong." She frowned. "And even if it's not, we're not married, so it's wrong anyways." She concluded crossing her arms.

"I still don't care." He muttered, running the brush down her golden locks.

* * *

The Zippleback landed on the forest, by the lake, as its twin owners commanded.

"Here, lots of eel for lunch!" Tuffnut announced dropping a huge basket in front of their pet.

The two heads of the Zippleback started fighting over the food and the twins laughed at how their pet resembled themselves.

"It's been a long time we don't fight…" Ruffnut said walking over a rock and leaning against it.

"And do other stuff too…" He grinned widely, walking towards the girl, intending to trap her against the rock. She smirked back and dodged from her brother's move, he tried again and she escaped laughing. When he finally caught her, they were on the opposite side of the rock.

She brought Tuffnut's mouth to hers and wrapped her arms tightly around his neck; Ruffnut threaded her fingers through his hair and pulled him closer, deepening the kiss and holding him as close to her as she could, he moaned as the taste of her lips seemed to send a jolt of electricity directly to his groin. The boy could feel his pulse in his hands, as he pressed himself against her.

He didn't care about what people would think. He couldn't even think. Her hands released his neck, moving over his shoulders and down his chest, mesmerized by the warmth and hard muscles under the fabric of his shirt.

Her arms tightened around him, her nails digging into his skin, underneath his clothes, as he placed wet kisses on her neck and chest making her head spin.

Soon he was running his thumbs over her nipples, under her half-undone clothes, as she wiggled her hips against his and moaned into his mouth. She parted to breathe, her hands working on his waistband as she panted. The simple contact with the skin of his hips made the muscles of her inner thighs tense up with anticipation.

"Tuff…" She moaned pressing her brother against her impatiently.

With a fierce move, he jerked his hips upwards making Ruffnut arch and moan loudly as he thrust into her. He held up her thighs and wrapped them around his waist, forcing himself to plunge deeper which caused him to grunt loudly and squeeze her legs tighter. For a moment he thought his knees would buckle, his cock pulsed intensely against her silky walls making shivers run down his spine.

Her small hands rested on his shoulders as she moaned softly, her eyes half closed; she arched at each forceful move he made.

He bent down and covered her mouth with his in a rough kiss; his calloused hands ran up to her waist as he pushed harder. Their muffled whimpers sounded like one as they moved faster, her insides convulsing around his cock as she came, being filled with his release just after.

They parted, breathlessly, and Tuffnut let himself lean on her, his legs were too weak for him to keep standing straight. She hugged him weakly.

He lifted himself up a little and brushed her hair away from her face, smiling lightly.

"I'm obsessed with you" He touched her forehead with his.


End file.
